- Steel Bridge Design Handbook: Design for Fatigue
- D. Mertz
- Book Title / Journal: Steel Bridge Design Handbook
- Year: 2012 , Volume: 12 , Series: FHWA-IF-12-052
- Bridge management ; Bridges
- Keywords: Steel bridges ; Fatigue
- Fatigue in metals is the process of initiation and growth of cracks under the action of repetitive tensile loads. If crack growth is allowed to go on long enough, failure of the member can result when the uncracked cross-section is sufficiently reduced such that the member can no longer carry the internal forces for the crack extends in an unstable mode. The fatigue process can take place at stress levels that are substantially less than those associated with failure under static loading conditions. The usual condition that produces fatigue cracking is the application of a large number of load cycles. Consequently, the types of civil engineering applications that are susceptible to fatigue cracking include structures such as bridges. This document provides the practicing engineer with the background required to understand and use the design rules for fatigue resistance that are currently a standard part of design codes for fabricated steel structures.